Clear up any deadlocks on Apple builds that were due to the...

Clear up any deadlocks on Apple builds that were due to the lldb_private::Process.m_private_run_lock variable. 

If someone on Linux and/or FreeBSD can try to comment out the " #if defined(__APPLE__)" that surrounds access to "m_private_run_lock" and run the test suite, that would be nice. The new location where the locking/unlocking happens is bulletproof on MacOSX, and I want to verify that it is good on linux as well.

llvm-svn: 181061